This disclosure is directed to a check valve for use in a pipeline. A check valve for a pipeline however is subject to certain constraints. Most pipelines are ordinarily cleaned through the use of pipeline pigs. Pigs are elongate bodies typically formed of polyurethane. They normally are either round or elongate bullet shaped bodies. Pipeline pigs are also used to separate different products. For instance, different petrochemical products can be pumped through a pipeline if they are separated by a sequence of pipeline pigs.
Quite often, check valves are required at spaced intervals in pipelines. Check valve must permit 100% of the flow of the pipeline in the required direction and must close against flow in the opposite direction.
The rate of rotation of a check valve in the pipeline is of interest. Normally, they are mounted on a hinge. The hinge includes a pin which in this disclosure is extended to the side. At the side of the housing itself, two things can be done advantageously with the pin. For one, the pin is exposed for connection to a hand operated handle. In the alternative, powered handles can be used. An easy example is the use of a hydraulic cylinder to rotate the pin and hence rotate the flapper valve attached to it. Another example is the use of a protruding pin to enable installation of a damping device. The present invention is particularly advantageous in that a damping device can be installed to dampen the jarring slamming shock occassioned when the flapper valve swings shut. This is very helpful. It prevents the flapper valve from chattering during the low flow rates. It also permits the use of a damping device to prevent slamming after a full gauge pig passes through the device. Pigs vary in shape but one common shape is an elongate pig. This keeps the flapper open for a longer interval. The present invention is thus able to be damped as the flapper valve falls back toward the closed position when the pig passes through the valve.
It is with these problems and others in mind that the present invention has been devised. This invention is in fact an improvement in that it provides a relatively inexpensive full opening check valve to be installed in a pipeline. It can be installed as illustrated and subsequently as desired, a fluid dampening mechanism or an external valve control lever mechanism can be connected to it.